A recipe for confusion – that is how a rail transport group has greeted news that passengers using new trains between Norwich and London will not be able to reserve seats for up to six months.

Greater Anglia's new Intercity trains operating between Norwich, Ipswich, Colchester and London are expected to come into service in the summer but rail bosses have warned that people will not be able to reserve seats, for a few weeks at least.

This is because there will be a period of time when both old and new trains will be running, but with different seating reservation systems.

Tickets such as Greater Anglia's cheaper Advance fares can still be purchased, and a specific train time selected.

But as the seating configuration inside the carriages on the new trains and the lettering on the outside is going to be different to the current trains, the seat reservations will be suspended until all the old carriages have been removed from service and all the new trains are running.

Chris Burton from Rail Future, which campaigns for a better passenger and freight network, said: 'It's a recipe for confusion between now and the future.' And he added that he thought it would 'annoy' people.

But Michael Fields, 54, from Wymondham, who was at Norwich Train Station yesterday, said it was good the rail firm was publicising the information about reservations.

He said: 'It's nice they are thinking of the customer rather than doing it on the day.'

A 24-year-old, who did not want to be named, but travels to London regularly said he did not think it would make much of a difference.

He said: 'Sometimes you reserve a seat, get on and there's not a reservation so there isn't really too much of a difference.'

Andrew Goodrum, Greater Anglia's business readiness director, said, 'The new trains coming into service is really exciting, but we wanted to avoid any mix ups with reservations while the two fleets are swapped over.'

He added: 'The new trains are much longer than our existing fleet so getting a seat during the transition won't be a problem.'

Seat reservations can still be booked from now up until Friday, July 12.